Modern telecommunications services are supported by a plurality of networks. The various networks operate under protocols that use packets of various lengths and formats to transfer data between a source and a sink. Modern telecommunications services provide the capability for business and social communications between geographically separated parties. This capability has stimulated a demand for such services and placed a burden on the capacity of existing infrastructure.
In order to increase the capacity for information exchange using the existing infrastructure, there has developed an interest in using asynchronous network facilities such as Asynchronous Transfer Mode (ATM) networks as backbone transport for voice and voice data as well as broadband services. Asynchronous network facilities are preferred for backbone transport because they permit more efficient use of network resources than synchronous transfer mode (STM) facilities. Network cost is therefore reduced. The ATM protocol uses a fixed cell length of 53 bytes. Consequently, packets originating in a network that operates under a different protocol must be deconstructed and packed in ATM cells before they can be transferred through the ATM network. After the packets are transferred through the ATM network, they must be unpacked from the cells and reconstructed before the cells are delivered to a sink. This is a time consuming task that can impact service delivery and quality of service.
Some telecommunications protocols such as Internet Protocol (IP) support packets of variable length. IP is unsuitable for certain telecommunications services, however, because it is connectionless and offers no guaranteed quality-of service. Recent work has been done to develop protocols for providing quality of service in IP networks. Resource Reservation Protocol (RSVP) is, for example, one result of such work. Even if quality of service is successfully implemented in IP networks, however, packet addressing and routing in such networks is too processing intensive to permit a high-speed multi-service scalable network to be implemented.
As the demand for telecommunications services increases, service providers seek cost effective methods of service delivery. One way to provide cost effective service delivery is to provide a backbone transport network that is capable of supporting a variety of narrow-band and broadband services so that network provisioning and management costs are shared by a large and diverse user base. Ideally, such a backbone transport network is adapted to support many different telecommunications services and both connection-based and connectionless protocols. To date, no such network is known to have been proposed or described.